title: Microphotoluminescence and perfect ordering of SiGe islands on pit-patterned Si(001) substrates.
abstract: We show that both the morphology and the optoelectronic properties of SiGe islands growing in the pits of periodically pre-patterned Si(001) substrates are determined by the amount of Ge deposited per unit cell of the pattern. Pit-periods (p) ranging from 300 to 900 nm were investigated, and Ge growth was performed by molecular beam epitaxy (MBE) at temperatures of 690 and 760 °C. The ordered SiGe islands show photoluminescence (PL) emission, which becomes almost completely quenched, once a critical island volume is exceeded. By atomic force and transmission electron microscope images we identify the transition from pyramid-shaped to dome-shaped islands with increasing p. Eventually, the nucleation of dislocations in the islands leads to PL quenching. Below a critical Ge coverage a narrowing and a blue shift of the PL emission is observed, as compared to islands grown on a planar reference area of the same sample.
authors.affiliation: Institute of Semiconductor and Solid State Physics, Johannes Kepler University Linz, Austria. florian.hackl@students.jku.at
authors.forename: Florian
authors.initials: F
authors.lastname: Hackl
authors.forename: Martyna
authors.initials: M
authors.lastname: Grydlik
authors.forename: Moritz
authors.initials: M
authors.lastname: Brehm
authors.forename: Heiko
authors.initials: H
authors.lastname: Groiss
authors.forename: Friedrich
authors.initials: F
authors.lastname: Schäffler
authors.forename: Thomas
authors.initials: T
authors.lastname: Fromherz
authors.forename: Günther
authors.initials: G
authors.lastname: Bauer
mesh_terms: D005857:Germanium / Q000737:chemistry*; D008163:Luminescent Measurements / Q000379:methods*; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012825:Silicon / Q000737:chemistry*
chemical_list: D005857:Germanium; D012825:Silicon